JPH0210727A - Method and apparatus for dividing semiconductor wafer - Google Patents

Abstract

PURPOSE:To enable the precise cutting and reduce the manufacturing cost by cutting a semiconductor wafer with impurity diffusion layers on both the surfaces thereof at the center into two pieces with a cutter rotating at a high speed at the fixed position with at least one surface of the wafer held. CONSTITUTION:A semiconductor wafer 1 with impurity diffusion layers on both the surfaces thereof is taken out of a cassette 12a with straight arms 13a with a function of attraction and carried to the specific position with a carrier mechanism. The wafer 1 is attracted with the attraction plate 9a of an arm 9 and rotated to be attracted to a holder 10. The holder 10 and the arm 9 are reciprocated vertically and the wafer 1 is cut at the center into two pieces with a cutter 7 rotating at a high speed. The two pieces of the wafer 1 are contained into a cassette 12b one by one with the arm 9 and the transfer mechanism. This enables precisely cutting the wafer into two pieces and using the pieces without post-processing to reduce the manufacturing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a semiconductor wafer dividing method and apparatus. More specifically, regarding a semiconductor wafer made of a disc-shaped silicon (SL) Il crystal used as a discrete element such as a transistor or a diode, an intermediate process means in the process of manufacturing and processing it as a substrate for a discrete element. and its apparatus.

[Prior Art] Conventionally, as a means for manufacturing substrates for discrete elements such as transistors and diodes made of semiconductor wafers made of disk-shaped silicon single crystals, the methods shown in FIGS. 6 to 8, for example, are known. ing.

The conventional means for manufacturing a substrate for discrete elements is to first cut and shape a semiconductor wafer 1 to a constant thickness using a diamond cutter or the like from an ingot made of a rod-shaped silicon single crystal, and then cut the semiconductor wafer 1 into a shape as shown in FIG. 1 is placed in a diffusion furnace or the like and impurities are diffused on both sides thereof to form an impurity diffusion layer 2. Thereafter, as shown in FIG.
One side of the semiconductor wafer 1 is ground to form an impurity undiffused layer 3 in which no impurities have been diffused, and new impurities 4, such as I, are added to the impurity undiffused layer 3 as roughly shown in FIG.・For transistors, new impurities are diffused to form the base, emitter, etc., and then they are made into chips and mounted.

[Problems to be Solved by the Invention] The above-mentioned conventional means for manufacturing a discrete 1-element substrate has a structure in which an impurity diffusion layer 2 and an impurity non-diffusion layer 3 must be provided on both sides of the semiconductor wafer 1. In order to cope with this problem, one side of the semiconductor wafer 1 is ground as shown in FIG. This has the problem that layer 2 is removed as chips.

In addition, as a means of solving such problems, the present inventors cut a semiconductor wafer having an impurity diffusion layer on both sides of which an impurity is diffused from the center of the J'J diameter into two parts. We have developed a technology in which each cut side of each semiconductor wafer is made into an undiffused impurity layer for diffusing new impurities. In this two-division technology, a simple two-division means is a development issue from the viewpoint of manufacturing efficiency.

The present invention has been made in view of these problems and development issues, and its purpose is to prevent the loss of the silicon monocrystalline impurity diffusion layer and the waste associated with its removal. It is an object of the present invention to provide a method for dividing a semiconductor wafer that can be easily carried out, and an apparatus for carrying out the method.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a semiconductor wafer dividing method and apparatus according to the present invention employs the following means.

That is, claim 1 relates to a method for dividing a semiconductor wafer, which comprises supplying a semiconductor wafer having impurity diffusion layers on both sides of which impurities are diffused to a cutter that rotates at high speed in a fixed position while holding at least -b one side. This method is characterized in that at least before the cutting is completed, the material is held from both sides and cut from the center of the thickness with a cutter to divide it into two parts.

Claim 2 also relates to a semiconductor wafer dividing apparatus, which includes: a holding mechanism capable of holding a semiconductor wafer having an impurity diffusion layer in which impurities are diffused on both sides from one side, a robot arm, and a robot arm for cutting the semiconductor wafer. The holding mechanism holds at least a semiconductor wafer and feeds it to the cutter so that the center of its thickness abuts the cutting edge, and the robotic arm holds at least a semiconductor wafer This means has an operating structure that continues to hold the material even before the cutting is finished.

[Operation] According to the above-mentioned bisecting technique of the present inventors, by dividing a semiconductor wafer having impurity diffused layers on both sides into two, it is possible to form an impurity-undiffused layer without performing the conventional heavy grinding described above. Therefore, loss of crystals in silicon and impurity diffusion layers and waste due to removal can be prevented.

According to the above-mentioned means, the semiconductor wafer thus divided into two parts is fed to the cutter rotating at high speed while holding at least one side, and when the cutting is completed, the semiconductor wafer is held from both sides, thereby making it possible to easily and accurately divide the semiconductor wafer into two parts. The purpose of making splitting possible is achieved.

[Example] Hereinafter, an example of a method for dividing a semiconductor wafer and an apparatus for dividing a semiconductor wafer according to the present invention will be described with reference to FIGS. 1 to 5.

First, to explain the two-parting technology developed by the present inventors, impurity diffusion layers 2 are formed on both sides as shown in FIG. 1(A).
A semiconductor wafer 1 having a wafer 1 is cut into two parts by cutting from the center of its thickness as shown in FIG. It is.

According to this two-division technique, the impurity diffusion layer i layer 2 of the semiconductor wafer 1 is used as is, and two discrete element substrates 1a and 1a' having the impurity undiffused layer 3 are formed from the - semiconductor wafer 1. That will happen. Therefore, the impurity diffusion 1i2 of the semiconductor wafer 1 is used as is and is not removed, and the loss of the silicon single crystal constituting the semiconductor wafer 1 is also reduced compared to the conventional case.

Further, FIG. 4 (conventional example) and FIG. 5 (two-part technique) compare the loss of the silicon single crystal described above.

In the conventional example, as shown in FIG. 4(A), a semiconductor wafer 1 having a thick thickness is cut and formed from an ingot 8 by consuming the cutting chip a, and as shown in FIG. 4(B), this semiconductor wafer is If the impurity diffusion I2 is formed in 1 and its thickness width remains unchanged as b (consumable wear due to polishing etc. is negligible and therefore ignored), then the grinding to form the impurity non-diffusion layer 3 will result in approximately half the thickness 1 /2b is consumed as a sliver, and a discrete element substrate 1' having a thickness of 1/2b is obtained as shown in FIG. 4(C). For this reason, 1/2
a for manufacturing one piece of discrete element substrate b
+ 1/2 bl of silicon single crystal will be consumed.

On the other hand, in the two-parting technique, as shown in FIG.
= 1/2b+1/2b+d+d+a,
〈a is the cutting cost of the semiconductor wafer 1, which is the same amount as the cutting edge of the ingot 8, and d is the surface modification formula 5. ), as shown in FIG. 5(C), two discrete rope substrates 1a and 1a' each having a thickness and width of 172b are finally obtained. For this reason, 1/2 (a+a+d+d)=a+dffi of silicon single crystals are consumed per manufacturing of one 1/2b discrete element substrate 1a, 1a', and the conventional consumption W!
In comparison with a + 1/2b, d is a sufficiently small amount in the current technology and d < 1/2b, so the present invention reduces consumption of the silicon single crystal.

In such a two-division technique, first, when forming the semiconductor wafer 1 by cutting the ingot 8, etc., the thickness and width of the semiconductor wafer 1 is formed to a thickness that can be divided into two, and then the semiconductor wafer 1 is formed into two parts. Detect the center of the thickness width and cutter 7
Now we will cut it into two parts from this center.

That is, in the embodiment of the present invention, as shown in FIG. 2 and FIG.
Consisting of 12a, 12b, 13a, and 13b, - middle, 11a is a belt conveyor, 11b is a roller conveyor, 12a is a cassette for storing wafers before cutting, 12b is a cassette for storing substrates after cutting (dividing into two), 13a is a cassette; a plate-shaped straight arm that conveys the wafer 1 from 12a to the roller conveyor Ilb;
b is a straight arm that conveys the substrate from the 0-ra conveyor 11b to the cassette 12b.

The cutter 7 rotates at a fixed position at a high speed to cut the semiconductor wafer 1, and is composed of a diamond cutter or the like having an inner circumferential blade 72 fixed under tension to a ring 71.

The botting arm 9 has a suction cup 9 at its tip via a telescoping mechanism 9b that connects to a vacuum pump or the like and generates a suction action in a timely manner.
A, the section from the downward direction to the horizontal direction is rotatable, and is installed so that it can be moved up and down.

The holding structure 10 is installed horizontally so as to intersect the cutter 7 at right angles, and has a strong adsorption surface 10a made of porous ceramic or the like at its tip leading to an intake path connected to a vacuum pump.

In this holding mechanism 10, the suction surface 10a is installed at a fixed position with reference to the inner circumferential blade 72 of the cutter 7, and is movable up and down by a mechanism not shown.

To explain the operation of the above-mentioned device, the lower surface of the wafers 1 is attracted by a plate-shaped straight arm 13a having a suction function on the upper surface of the tip, and the wafers 1 are taken out one by one from the cassette 12a and conveyed to the roller conveyor 11b. Thereafter, the wafer 1 is conveyed to a predetermined position by the conveyor Ilb and the belt conveyor 11a, where the robot arm 9 suctions the wafer 1 with a suction cup 9a, rotates upward, and transfers it to the suction surface 10a of the holding mechanism 10. let During this time, the wafer 1 in the cassette 12a is held in the straight arm 13.
The paper is lifted up to the position where it is picked up by a, and preparation for the next conveyance is completed.

When the suction surface 10a of the holding mechanism 10 suction-holds the wafer 1, the suction cup 9a of the robot arm 9 stops its suction action, firmly suction-holds the wafer 1 on the suction surface 10a, and holds the wafer 1 well. The mechanism 10 and the robotic arm 9 move upward, and the cutter 7 cuts the wafer 1 from its center into two parts (as shown by the two-dot broken line in FIG. 2).

Before the cutter 7 finishes cutting, the suction cup 9a of the robot arm 9 resumes its suction action to suction and hold the substrate 1a', which is the cut half of the wafer 1. After cutting, the holding mechanism 10 descends while holding the substrate 1a, which is the other half of the wafer 1, and the telescopic mechanism 9b contracts while the robot arm 9 holds the substrate 1a' on its suction cup 9a. In this state, the substrate 1a' is lowered while rotating downward, and when it is located on the belt conveyor 11a, the contraction operation is canceled and the substrate 1a' is placed on the belt conveyor 11a. The substrate 1a' transferred from the belt conveyor 11a to the roller conveyor 11b has its lower surface attracted by the straight arm 13b, and is transported and stored in the cassette 12tl.

After the holding mechanism 10 returns to the base position, the substrate 1a held on the suction surface 10a of the mechanism 10 is also moved onto the belt conveyor 11a by the above-described operation of the robotic arm 9.
It is conveyed upward and is conveyed and stored in the cassette 12b by the straight arm 13b transferred to the roller conveyor 11b. Then, the cassette 12b is lifted up by the pitch of the substrate 1a.

Next, a new wafer 1 is taken out from the cassette 12a by the straight arm 13a, and the same operations as described above are repeated.

In the above embodiment, only one belt conveyor 11a is provided and used as the conveyance path for the wafer 1 and the substrates 1a and 1a', but in order to increase the working speed, two systems with separate conveyance paths are used. A belt conveyor may also be installed.

Furthermore, it is optional to use another roboting arm in addition to the roboting arm to collect the substrate 1a held on the suction surface 10a of the holding mechanism 10, thereby further increasing the work speed.

Furthermore, in the embodiment, a case has been described in which the holding mechanism 10 is moved up and down to perform the cutting operation, but the holding mechanism 10 is
It is also optional to perform the cutting operation by fixing the cutter 7 in a fixed position and moving the cutter 7 up and down.

[Effects of the Invention] As described above, in the semiconductor wafer dividing method and apparatus according to the present invention, the reference plane in the holding mechanism remains unchanged even during repeated operations after being set at a predetermined position, and therefore the wafer held therein remains unchanged even during repeated operations. This has the effect of making it possible to cut (divide into two) extremely accurately with respect to the reference plane.

Furthermore, silicon single crystal is an effect of the above-mentioned two-division technology for producing substrates for discrete devices.

This has the effect of preventing loss of the impurity diffusion layer and waste due to removal, and thereby contributing to a reduction in manufacturing cost.

[Brief explanation of the drawing]

FIGS. 1A and 1B are cross-sectional views showing a two-parting technique that is a prerequisite technology for the semiconductor wafer dividing method and apparatus according to the present invention, and FIG. 2 is a semiconductor wafer dividing method and apparatus according to the present invention. A front view showing the embodiment, FIG. 3 is a plan view thereof,
Figure 4 (A). (B) and (C) are cross-sectional views showing the amount of consumption of a silicon single crystal (conventional example). The sectional views of the dividing technique, FIGS. 6 to 8, are sectional views showing the steps of the conventional example. 1... Semiconductor wafer 2... Impurity diffusion layer 3
... Impurity undiffused layer 4... New impurity 7...
・Cutter 8... Ingot 9... Robotic arm 10... Holding mechanism Patent applicant Naoetsu Electronics Co., Ltd.

Claims (2)

[Claims] (1) A semiconductor wafer having an impurity diffusion layer on both sides with impurities diffused therein is held at least on one side and fed to a cutter rotating at high speed in a fixed position, and at least before the cutting is completed, the semiconductor wafer is held from both sides and cut into thickness with the cutter. A method for dividing a semiconductor wafer, characterized by cutting from the center of the semiconductor wafer and dividing the semiconductor wafer into two parts. (2) A holding mechanism that can hold a semiconductor wafer having an impurity diffusion layer on both sides from one side, a robot arm, and a cutter that can rotate at high speed in a fixed position to cut the semiconductor wafer into two parts. The holding mechanism holds the semiconductor wafer and supplies the semiconductor wafer to the cutter so that the center of its thickness comes into contact with the cutting edge, and the robotic arm has an operating structure that continues to hold the semiconductor wafer at least before the cutting of the semiconductor wafer is completed. A semiconductor wafer dividing device comprising: